凡纳滨对虾生长与高氨氮耐受性的遗传力及选择反应研究

Selection response and heritability of growth and high ammonia nitrogen tolerance of Litopenaeus vannamei

基于选择指数法对凡纳滨对虾(Litopenaeus vannamei)生长和高氨氮耐受性进行选择,用3种方法评估选择效果:Ⅰ)比较选择系和对照系相关性状的育种值;Ⅱ)比较选择家系和对照家系的最小二乘均值;Ⅲ)比较选择系与对照系表型值,计算相关性状的现实遗传力、遗传获得,并采用BLUP法估算相关性状的遗传力及遗传相关。结果显示,生长性状的选择反应为0.493~1.039,高氨氮耐受存活的选择反应为0.028~0.046;凡纳滨对虾生长性状的现实遗传力为0.288~0.315,遗传获得为6.45%~20.16%,高氨氮耐受成活率的现实遗传力为0.016,遗传获得为2.09%;BLUP法估算生长性状遗传力为0.216~0.284,且显著(P<0.05),高氨氮耐受性遗传力为0.028±0.026,生长性状间呈高度遗传正相关为0.871~0.948,体质量与高氨氮耐受性间的正遗传相关为0.180±0.032,且显著(P<0.05)。研究表明,采用选择指数法选育一代后,生长性状提高明显,高氨氮耐受性提高较小;选育群体生长性状具有较大遗传改良潜力,如何快速提高选育群体的高氨氮耐受性有待进一步研究。

Based on index selected method, we evaluated the growth and tolerance to high ammonia nitrogen of Litopenaeus van- namei by comparing the breeding values, the least squares means and phenotypic values of related growth traits between selected line and control line. The realized heritability and genetic gain were estimated. The heritability and genetic correlation of related traits of L. vannamei were also estimated by best liner unbiased prediction method （BLUP）. The results show that the selection response for growth traits and high ammonia nitrogen tolerance were 0. 493 - 1. 039 and 0. 028 - 0. 046, respectively. The realized heritability and genetic gain for growth traits were 0. 288 - 0. 315 and 6. 45% - 20. 16% , respectively. The realized heritability and genetic gain for high ammonia nitrogen tolerance were 0. 016 and 2. 09% , respectively. The heritability estimated by BLUP for growth traits and high ammonia nitrogen tolerance were 0. 216 - 0. 284 （ P 〈 0. 05 ） and 0. 028 -0. 026, respectively. The genetic correlation between growth traits was 0. 871 - 0. 948 （ P 〈 0. 05 ）, and that between high ammonia nitrogen tolerance and body weight was 0. 180 ±0. 032 （P 〈 0.05 ）. It is concluded that index selection method is an effective approach to improve growth traits of L. vannamei; besides, the selection population has moderate heritability to enable further improvement but relatively small improvement for high ammonia nitrogen tolerance, which suggests that breeding selection needs further study to improve high ammonia nitrogen tolerance.